| Summary: | 碩士 === 國立高雄應用科技大學 === 化學工程與材料工程系博碩士班 === 106 === Graphene was prepared at different voltages firstly.And then nickel foam was immersed in graphene to prepare graphene/nickel foam composite material. The results of the study showed the higher voltage has the lower electrochemical exfoliation effect, making the sulfate ions harder diffusion to interlayers of graphite effectively. MnO2 electrode was prepared by constant current deposition at different current density. The results of cyclic voltammetry showed that the smaller current density was the smaller MnO2 nanostructure prepared, which is beneficial to the contact between MnO2 nanostructure and electrolyte, increases the capacitance.
The MnO2/nickel foam electrode prepared at a constant current density of 5 mA/cm2, 10 mA/cm2, and 15 mA/cm2 has a capacitance of 179 F/g、152 F/g and 96 F/g at scan rate 10 mV/s, orespectirely. The MnO2/graphene/nickel foam electrode has capacitance value of 221 F/g, 159 F/g, and 133 F/g, confirming that graphene contributes to increase in capacitance. After 1000 cycles, the MnO2/Nickel foam retention rate was 84 % and the MnO2/graphene/nickel foam capacity retention rate was increased to 90 %, confirming that graphene not only supported electrons are but also conductive to increase the capacitance retention and increase the stability of the electrode sheet.
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